Mill for manufacturing bodies of multilayer high-pressure vessels

ABSTRACT

A mill for manufacturing bodies of multilayer high-pressure vessels comprises rotators (3) of the body (1) of the high-pressure vessel, which have the butt end portions of the body (1) of the high-pressure vessel secured therein. The body (1) of the high-pressure vessel is surrounded by a portal (5) capable of moving along the body (1) of the vessel. An upper platform (8) of the portal (5) carries a technological line (15) for preparation of the steel strip for its winding onto a central pipe (16) of the body (1) of the vessel, the steel strip (2) being supplied from a coil (18). A crossbar (9) secured to uprights (10) of the portal (5) carries an arrangement (32) for tensioning the steel strip, which can move along the crossbar (9) and from which the steel strip (2) is supplied to the upper generatrix of the body (1) of the vessel in such a manner that a free loop ( 30) of the steel strip (2) allowing for a turn of the arrangement (32) for tensioning the steel strip in the horizontal plane is formed between the technological line (15) for preparation of the steel strip for its winding onto the central pipe (16) of the body (1) of the vessel and the arrangement (32) for tensioning the steel strip. The mill also comprises a fixture for welding the steel strip (2) to the end portions of the body (1) of the vessel and turns of the steel strip (2) to one another.

TECHNICAL FIELD

The present invention relates to systems for manufacturing helical seampipes and, more particularly, to mills for manufacturing bodies ofmultilayer high-pressure vessels.

BACKGROUND OF THE INVENTION

Multilayer high-pressure vessels manufactured by way of helical windingof a steel strip onto a central pipe in such a manner that everysubsequent layer is placed in the direction opposite to that of thepreceding one have no fastening welding seams or have only partialfastening in some outer layers of the steel strip. As a result, thestrength of the high-pressure vessels depends on tightness of adherenceof the strip layers to one another and accuracy of the steel stripwinding. The tightness of adherence of the steel strip layers to oneanother and the accuracy of the steel strip winding depend, in theirturn, on the value of tensioning of the steel strip being wound and theaccuracy of adjustment of the angle of feeding of the steel strip to bewound. The rolled steel strip is inevitably crescent-shaped and hasdeviations in its width. Said deviations require an additionaladjustment of the present angle of the steel strip winding in the courseof winding. Therefore, rigidity and stability of the systems used forwinding the steel strip, as well as an accurate adjustment and a fastcorrection of the parameters of the steel strip winding depending oncurrent deviations in the shape of the steel strip are of a paramountimportance during manufacture of bodies of multilayer high-pressurevessels.

Widely known is a plant for manufacturing helical seam pipes made of twostrips (FRG Pat. No. 1222456; Class 7b, 37/12, published in 1962), whichcomprises a shaping unit bending the steel strip into a spiral and twotechnological lines for preparation of the steel strip, located at theopposite sides in relation to the pipe axis. Each technological line forpreparation of the steel strip comprises a decoiler, drive rollersfeeding the steel strip to the pipe, a straightening machine, anarrangement for cutting the steel strip, a fixture for butt welding ofthe ends of the steel strip and guide rollers, all arranged insuccession along the direction of movement of the steel strip, all thisequipment being mounted on a common frame installed on railways andcapable of turning in the horizontal plane to change the angle offeeding of the steel strip during the winding thereof.

The afore-said device is characterized by a low accuracy of setting andadjustment of the angle of feeding of the steel strip because theprocess of setting and adjustment of the feeding angle of the steelstrip necessitates a turn of the whole technological line forpreparation of the steel strip, which is of a great weight and largedimensions. The plant under description used for manufacturing helicalseam pipes occupies a considerable production area as the technologicallines for preparation of the steel strip are located at the oppositesides of the pipe axis.

Also widely known is a mill for manufacturing bodies of multilayerhigh-pressure vessels (U.S. Pat. No. 2,600,630; Class 29-446, publishedin 1952), comprising rotators of the body of the high-pressure vessel,which have the butt end portions of the high-pressure vessel securedtherein, and a technological line for preparation of the steel strip forits winding onto the vessel central pipe, the steel strip coming from acoil. The technological line for preparation of the steel stripcomprises a decoiler, straightening rolls and guide rollers, allarranged in succession down the direction of movement of the steelstrip. The technological line for preparation of the steel strip ismounted on a frame installed on a carriage moving along railways, therailways being positioned parallel to the high-pressure vessel bodybeing wound at one side thereof, the movement of the carriage beingmechanically matched to the rotation of the high-pressure vessel body.The frame mounting the technological line for preparation of the steelstrip is made capable of turning in the horizontal plane to feed thestrip to the vessel at a winding angle.

The mill also comprises an arrangement for tensioning the steel strip,which is mounted, relative to the axis of the vessel body, at an anglecorresponding to the angle of winding of the steel strip and is movablealong the high-pressure vessel body. The fixture for welding the steelstrip to the end portions of the vessel body and turns of the steelstrip to one another can also move relative to the vessel body.

The above-mentioned mill for manufacturing bodies of multilayerhigh-pressure vessels does not provide for a sufficient tightness andaccuracy of winding of the steel strip because, when setting andadjusting the angle of winding of the steel strip, all the equipment ofthe technological line for preparation of the steel strip has to beturned around, this being still worse in case the layer of the steelstrip is wound several times and in opposite directions. The fact thatthe carriage carrying the equipment of the technological line forpreparation of the steel strip is mounted at one side of thehigh-pressure vessel body reduces rigidity and stability of themechanical system of the mill during winding up of the body of a vesselof a big diameter when the tension of the steel strip is great. In thecase of winding up of the bodies of vessels of great dimensions andweight the mechanical matching between the movement of the technologicalline for preparation of the steel strip along the high-pressure vesselbody and the rotation of the body of the high-pressure vessel does notprovide for an accurate winding of the steel strip owing to a lowrigidity of the mechanical system of the mill being described. Whenchanging the direction of winding of the steel strip, the equipment ofthe technological line for preparation of the steel strip has to be putat the other side, which results in wasted work time. Besides, everytime a new layer is to be wound the end of the steel strip is chamferedat an angle which is a mirror reflection of the angle of winding of theprevious layer, which brings about an excessive consumption of metal.

DISCLOSURE OF THE INVENTION

The present invention has as its object to provide a mill formanufacturing bodies of multilayer high-pressure vessels, in which aspecific positioning of the technological line for preparation of thesteel strip and the arrangement for tensioning the steel strip relativeto the body of the high-pressure vessel provides for an improved qualityof bodies of high-pressure vessels, and greater accuracy and tightnessof adherence of layers of the steel strip of the body to one another.

This object is accomplished by that the mill for manufacturing bodies ofmultilayer high-pressure vessels, comprising rotators of thehigh-pressure vessel body, which have butt end portions of thehigh-pressure vessel body secured therein, a technological line forpreparation of the steel strip coming from a coil for winding onto thecentral pipe of the vessel body, which can move along the body of thehigh-pressure vessel, an arrangement for tensioning the steel strip,which is mounted, relative to the axis of the vessel body, at an anglecorresponding to the angle of winding of the steel strip and which canalso move along the body of the high-pressure vessel, and a fixture forwelding the steel strip to the end portions of the vessel body and turnsof the steel strip to one another, which is also movable along thevessel body, which mill, according to the invention, additionallycomprises a portal which surrounds the vessel body, can move along thelatter and whose upper platform upholds a technological line forpreparation of the steel strip for its winding onto the central pipe ofthe vessel body and a crossbar secured to uprights of the portal so thatit can move vertically the mounts of the arrangement for tensioning thesteel strip which can move along the crossbar and from which the steelstrip is supplied to the upper generatrix of the vessel body in such amanner that a free loop of the steel strip allowing for a turn of thearrangement for tensioning the steel strip in the horizontal plane isformed between the technological line for preparation of the steel striponto the central pipe of the vessel body and the arrangement fortensioning the steel strip.

In order to further raise the accuracy and tightness of adherence oflayers of the steel strip to one another, it is expedient that the millcomprises an additional technological line for preparation of the steelstrip for its winding onto the central pipe of the vessel body, disposedon the upper platform of the portal and an additional arrangement fortensioning the steel strip, disposed on the crossbar of the portal inthe same horizontal plane as the main arrangement for tensioning thesteel strip, the main and additional technological lines for preparationof the steel strip for its winding onto the central pipe of the vesselbody being disposed, relative to the plane perpendicular to the axis ofthe vessel body, at an angle determined by the angle and direction ofwinding of the steel strip.

TECHNICAL AND ECONOMIC EFFECT

The mill for manufacturing bodies of multilayer high-pressure vesselsprovides for an accurate and tight winding of the steel strip as it isof a rigid and stable structure and performs adjustment of the angle ofwinding of the steel strip by way of displacement of the arrangement fortensioning the steel strip while the rest of the equipment remainsstationary.

The mill is highly efficient as it allows for the reduction of the timerequired for preparation of the front end of the steel strip, settingand adjustment of the angle of winding of the steel strip, and tocombine the operations of preparation of the steel strip in onetechnological line for preparation of the steel strip with theoperations of winding the steel strip supplied from the othertechnological line for preparation of the steel strip.

Use of the mill makes it possible to reduce wastes of metal duringpreparation of the end portions of the steel strip for winding everysubsequent layer by eliminating wastes when cutting beveled end portionsof the steel strip.

Besides, use of the mill of the invention makes it possible to decreasethe production area required for manufacture of bodies of multilayerhigh-pressure vessels.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be more readily understood from the followingdescription of specific variants of its embodiment and drawings inwhich:

FIG. 1 shows a general view of the mill for manufacturing bodies ofmultilayer high-pressure vessels, having one technological line forpreparation of the steel strip for its winding onto the central pipe ofthe vessel (a side view with a partial extraction), according to theinvention;

FIG. 2 shows a general view of another variant of embodiment of the millfor manufacturing bodies of multilayer high-pressure vessels, having twotechnological lines for preparation of the steel strip for winding ontothe central pipe of the vessel (a top view), according to the invention;

FIG. 3 shows a general view of the mill for winding up bodies ofmultilayer high-pressure vessels, with two technological lines forpreparation of the steel strip (a front view), according to theinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

A mill for manufacturing bodies 1 of multilayer high-pressure vessels,wound up of a steel strip 2, comprises rotators 3 of the body of thehigh-pressure vessel, whose chucks 4 have the butt end portions of thevessel body 1 secured therein. The mill also comprises a portal 5 whichsurrounds the high-pressure vessel body 1 being wound up and which ismounted on wheels 6 on a railway 7 capable of moving along the body 1 ofthe high-pressure vessel. The portal 5 comprises an upper workingplatform 8, a crossbar 9, front uprights 10 and rear uprights 11.

The front uprights 10 are interconnected by a beam 12 and the rearuprights 11 are interconnected by a beam 13, the beams 12 and 13mounting drives 14 of the wheels 6 of the portal 5.

A technological line 15 for preparation of the steel strip 2 for itswinding onto the central pipe 16 of the body 1 of the high-pressurevessel is mounted on the upper platform 8 of the portal 5perpendicularly to the axis of the body 1 of the high-pressure vessel.

The technological line 15 for preparation of the steel strip comprises adecoiler 17 whose rollers 17' uphold a coil 18 of the steel strip 2.Further down the direction of movement of the steel strip 2 there ispositioned a multiroll straightening machine 19 with rollers 20 betweenwhich the steel strip 2 is drawn. Installed behind the straighteningmachine 19 is a gas cutter 21 (not shown in the drawing) for cutting thesteel strip 2. Farther down there is mounted a butt welding machine 22which comprises an electric welding head 23, front clamps 24 of the endof the steel strip with hydraulic cylinders 25 disposed before theelectric welding head 23 relative to the direction of movement of thestrip 2 and rear clamps 26 with hydraulic cylinders 27 disposed behindthe electric welding head 23 relative to the direction of movement ofthe steel strip 2. Disposed behind the butt welding machine 22 inrelation to the direction of movement of the steel strip 2 are feedrollers 28 with a deflecting roller 29 used to form a loop 30 out of thesteel strip 2 between the upper platform 8 and the crossbar 9 of theportal 5.

The crossbar 9 is secured to the front uprights 10 of the portal 5 andcan move vertically with the aid of a screw mechanism 31 having a drive(not shown in the drawing).

The crossbar 9 carries an arrangement 32 for tensioning the steel strip,which is made as a multiroller machine, upper rollers 33 of thearrangement 32 for tensioning the steel strip being capable of movingvertically relative to lower rollers 34 to change the force oftensioning of the steel strip 2. The arrangement 32 for tensioning thesteel strip also comprises a roller 35 disposed under one of the lowerrollers 34 and used to feed the end of the steel strip 2 until thetensioning force is applied.

The arrangement 32 for tensioning the steel strip has a frame 32' whichis mounted on sleds 36 with the aid of journals 37 and can be turned inthe horizontal plane around the journals 37 by means of a hydraulicdrive 38 mounted on the sleds 36 and coupled with the frame 32' of thearrangement 32 for tensioning the steel strip.

The sleds 36 are capable of moving along the crossbar 9 by means of ahydraulic drive 39 to decrease the transverse deformation of the loop 30of the steel strip 2.

The hydraulic drive 39 is mounted on the crossbar 9 and is coupled withsleds 36 mounting the frame 32' of the arrangement 32 for tensioning thesteel strip.

The crossbar 9 carries a platform 40 used for servicing and providedwith a control panel 41.

Mounted from the bottom of the upper platform 8 of the portal 5 is aclamping device 42 and a fixture 43 for welding the steel strip 2 to thebutt end portions of the body 1 of the high-pressure vessel and turns ofthe steel strip 2 to one another, which is installed for movementrelative to the body 1 of the high-pressure vessel.

The lower beam 12 has thrust rollers 45 mounted in slide guides 44 andused to counterbalance the force of tensioning of the steel strip 2,acting upon the body 1 of the high-pressure vessel in the course ofwinding, and two milling heads 46 for machining weld seams.

There is possible another variant of embodiment of the mill formanufacturing bodies 1 of multilayer high-pressure vessels.

In this case the mill comprises all the afore-described units plus anadditional technological line 47 (FIG. 2) also mounted on the upperplatform 8 of the portal 5, and an additional arrangement 48 fortensioning the steel strip (FIG. 3) which is also mounted on thecrossbar 9 in the same horizontal plane as the main arrangement 32 fortensioning the steel strip, the main technological line 15 (FIG. 2) forpreparation of the steel strip and the additional technological line 47for preparation of the steel strip being disposed at an angle α relativeto a plane 49 perpendicular to an axis 50 of the body 1 of thehigh-pressure vessel.

The angle α is determined by the angle of winding of the steel strip 2,and, when manufacturing the bodies 1 of high-pressure vessels withdifferent angles of winding of the steel strip, the angle α is chosen asa mean value between the maximal and minimal values of the angle ofwinding of the steel strip to decrease bending of the loop 30 of thesteel strip 2 in the transverse direction.

With respect to the plane 49, the technological lines 15 and 47 forpreparation of the steel strip are turned in opposite directions, themain technological line 15 for preparation of the steel strip being usedduring winding in one direction, e.g. from left to right, and theadditional technological line 47 for preparation of the steel stripbeing used during winding in the opposite direction, e.g. from right toleft. Like the main technological line 15 for preparation of the steelstrip, the additional technological line 47 for preparation of the steelstrip also comprises a decoiler 17. Arranged farther down the directionof movement of the steel strip 2 is the multiroller straighteningmachine 19 with the rollers 20 (FIG. 1) between which the steel strip 2is drawn. Mounted behind the straightening machine 19 (FIG. 2) is thegas cutter 21 cutting the steel strip 2. Mounted further down thedirection of movement of the steel strip is the butt welding machinewhich comprises the electric welding head 23, the front clamps 24 forthe ends of the steel strip, provided with the hydraulic cylinders 25and the rear clamps 26 provided with the hydraulic cylinders 27.Disposed behind the butt welding machine 22 relative to the direction ofmovement of the steel strip 2 are the feed rollers 28 provided with thedeflecting rollers 29, rollers 17' of the decoiler 17 of thetechnological line 47 mounting another coil 18' of the steel strip 2.

The additional arrangement 48 (FIG. 3) for tensioning the steel strip ismade similar to the main arrangement 32 for tensioning the steel stripas a multiroller machine and is also mounted on the sleds 36 with theaid of the journals 37. It is provided with the individual hydraulicdrive 38 used for turning the arrangement 48 for tensioning the steelstrip around the journals 37, and with the hydraulic drive 39 moving thearrangement 48 along the crossbar 9.

The hydraulic drive 38 is mounted on the sleds 36 and is connected withthe frame 32' of the arrangement 32 for tensioning the steel strip. Thehydraulic drive 39 is mounted on the crossbar 9 and is connected withthe sleds 36 mounting the frame 32' of the arrangement 32 for tensioningthe steel strip.

The screw mechanisms 31 (FIG. 2) used for moving vertically the crossbar9 are kinematically interconnected and have a common drive 51.

The mill for manufacturing the bodies 1 of multilayer high-pressurevessels operates as follows.

The butt end portions of the body 1 of the high-pressure vessel, weldedto the central pipe 16 onto which the steel strip 2 is wound are securedin the chucks 4 (FIG. 1) of the rotators 3.

The coil 18 of the steel strip 2 is placed onto the decoiler 17, and thesteel strip 2 is fed from the decoiler 17 owing to rotation of therollers 17' into the straightening machine 19 in which the rollers 20straighten the steel strip 2, and feed it through the cutter 21 in whichit is cut at the angle of winding of the first layer from onelongitudinal edge to the other one in such a manner that the length ofthe cut equals the length of the outer circumference of the central pipe16. Then, the steel strip 2 is passed through the butt welding machine22 to the feed rollers 28. The deflecting roller 29 of the feed rollers28 deflects the steel strip 2 downwards to form the loop 30 and feeds itinto the space between the rollers of the arrangement 32 for tensioningthe steel strip, with the formed wastes of the steel strip 2 beingsimultaneously removed from the mill.

The steel strip 2 is pressed by the roller 35 against one of the driverollers 34 and is fed farther to the central pipe 16.

The crossbar 9 with the arrangement 32 for tensioning the steel stripand the steel strip 2 are moved vertically by the screw mechanisms 31until the steel strip 2 touches the upper generatrix of the central pipe16.

The hydraulic drive 38 turns the arrangement 32 for tensioning the steelstrip through the angle of winding. While being turned around thejournals 37, the arrangement 32 for tensioning the steel strip isadditionally moved on the sleds 36 along the crossbar 9 by the hydraulicdrive 39. The arrangement 32 for tensioning the steel strip is movedalong the crossbar 9 to decrease transverse deformation of the loop 30of the steel strip 2.

By moving the portal 5 the cut edge of the steel strip 2 is brought tothe left-hand butt end portion of the body 1 of the multilayerhigh-pressure vessel. The end of the steel strip 2 is spot-welded to thebutt end portion of the body 1 of the high-pressure vessel by thefixture 43 for welding the steel strip, the clamping device 42 isbrought down onto the fixed end of the steel strip 2, the rotators 3 arestarted up and the beveled edge of the steel strip 2 is welded by thefixture 43 to the butt end portion of the body 1 of the high-pressurevessel along the length of a complete circumference. With the end of thesteel strip 2 welded thereto, the steel strip is tensioned by loweringthe upper rollers 33 between the front rollers 34. Then, the thrustrollers 45 are brought up to the side surface of the central pipe 16,and further winding of the steel strip 2 is accompanied by simultaneousand synchronized rotation of the body 1 of the vessel and translationalmovement of the portal 5 along the axis 50 of the vessel body 1. By thetorque created by the rotators 3 the steel strip 2 is drawn from thearrangement 32 and is wound onto the central pipe 16 with some tension.

In case the steel strip 2 starts having deviations in its width oraquiring a crescent shape, as well as in order to prevent one turn fromrunning over another and to maintain a preset gap between the edges ofthe adjacent turns, the angle of winding is corrected by turning thearrangement 32 for tensioning the steel strip 2 around the journals 37with the aid of the hydraulic drive 38. Whenever necessary, thearrangement 32 for tensioning the steel strip is moved along thecrossbar 9 by means of the hydraulic drive 39. Before winding of thefirst layer is completed the gas cutter 21 is switched on to cut off thesteel strip 2 at the angle of winding of the first layer to shape therear end of the steel strip 2 of the first layer, whereupon the steelstrip 2 is cut off at the angle of winding of the second layer to shapethe front end of the steel strip 2 of the second layer.

Thereupon, the decoiler 17 and the multiroller straightening machine 19are stopped and the rear end of the steel strip 2 is wound onto thecentral pipe 16 until the beginning of the cut reaches the right-handbutt end portion of the body 1 of the high-pressure vessel, whereuponthe translational movement of the portal 5 is discontinued and the cutedge is welded to the right-hand butt end portion of the body 1 of thehigh-pressure vessel under the clamping force of the device 42.

Prior to winding of another layer of the steel strip 2 the both weldseams are machined by the milling heads 46 during rotation of the body 1of the high-pressure vessel. To wind the second layer, the decoiler 17and the straightening machine 19 are started, the steel strip 2 shapedat the angle of winding is brought through the butt welding machine 22to the feed rollers 28, the deflecting roller 29 forms the loop 30 fromthe steel strip 2 and, at the same time, wastes of the steel strip 2 areremoved from the mill. The steel strip 2 is fed into the arrangement 32for tensioning the steel strip and is brought up to the upper generatrixof the cylindrical surface of the first layer of the vessel body 1 as ithas been described before.

The hydraulic drive 38 turns the arrangement 32 for tensioning the steelstrip through the angle of winding of the second layer, whicharrangement 32 is simultaneously moved along the crossbar 9.

By moving the portal 5, the cut-off edge of the steel strip 2 is broughtup to the right-hand butt end portion of the body 1 of the high-pressurevessel and is welded to the right-hand butt end portion of the body 1 ofthe high-pressure vessel in the sequence described before.

The steel strip 2 is tensioned and further wound while the body 1 of thehigh-pressure vessel is constantly rotated and the portal 5 istranslationally moving in the reverse direction.

The rear end of the steel strip 2 of the second layer is shaped andwelded to the left-hand butt end portion in the same sequence asdescribed for the first layer.

All the subsequent layers of the steel strip 2 are wound and welded inthe same manner.

As manufacture of one multilayer body 1 of the high-pressure vesselrequires several coils of the steel strip 2, the ends of the steelstrips 2 are welded together in the course of winding.

For this, the ends of the steel strips 2 to be joined are preliminarilycut off and are then welded together in the butt welding machine 22.During their cutting-off and welding together the ends of the steelstrips 2 are pressed by the respective clamps 24 and 26 with the aid ofthe hydraulic cylinders 25, 27.

If necessary, layers of the steel strip 2 are welded together along theedges of the adjacent turns by the fixture 43, the weld seams beingmachined by the milling heads 46.

During the operation of the mill for manufacturing the bodies 1 ofmultilayer high-pressure vessels, comprising the additionaltechnological line 47 (FIGS. 2, 3) for preparation of the steel strip 2and the additional arrangement 48 for tensioning the steel strip, thesteel strip 2 wound in one direction is fed from the main technologicalline 15 through the main arrangement 32 for tensioning the steel strip,whereas the steel strip 2 wound in the opposite direction is fed fromthe additional technological line 47 through the additional arrangement48 for tensioning the steel strip 2.

Thereby, the steel strip 2 is cut off in the cutter 21 without changingthe direction of the cut relative to the edges of the steel strip 2 foreach of the technological lines 15, 47 for preparation of the steelstrip.

Employment of the main and additional arrangements 32 and 48 (FIG. 3)for tensioning the steel strip eliminates the operation of their turningin the horizontal plane when changing the direction of winding. Thehydraulic drives 38 turn slightly the arrangements 32 and 48 for themere purpose of correcting the angle of winding of the steel strip 2when passing over from one layer to another and in the cases ofdeviations in the width of the steel strip or appearance of the crescentshape, which, in its turn, brings down the necessity for additionalmovement of the arrangements 32 and 48 for tensioning the steel stripalong the crossbar 9.

Use of the mill for manufacturing bodies of high-pressure vessels makesit possible to increase the number of layers of the steel strip woundhelically in opposite directions and provides, at the same time, highaccuracy and tightness of the winding, thereby improving reliability ofhigh-pressure vessels and safety of their operation.

The mill for manufacturing bodies of high-pressure vessels makes itpossible to raise labour efficiency, and to reduce the production areaand consumption of metal.

Industrial Applicability

The present invention can be used in machine building when manufacturingfrom a steel strip multilayer high-pressure vessels such as columns forsynthesis of ammonia, carbamide and methanol, reactors for hydrauliccracking of petroleum products, apparatus for heat- and mass-exchangeunder high pressure of nuclear reactions.

We claim:
 1. A mill for manufacturing bodies of multilayer high-pressurevessels, said mill comprising: a high-pressure vessel having a body inthe form of a central pipe including butt end portions; means to rotatethe high-pressure vessel, said butt end portions of the high-pressurevessel secured in said rotating means; a technological line forpreparation of a steel strip for its winding onto the central pipe, saidtechnological line being movable along the body of the high-pressurevessel, said steel strip coming from a coil; first tensioning means fortensioning the steel strip and pivotally mounted in a plane tangentialto the vessel body and at an angle relative to the axis of the vesselbody, said angle corresponding to the angle of winding of the steelstrip, said tensioning means being also movable axially along the bodyof the high-pressure vessel and including a plurality of rollersdisposed on opposite sides of the steel strip and movable toward andaway from each other to change the tension in the strip between thetensioning means and the vessel body; a fixture for welding the steelstrip to the end portions of the vessel body and for welding turns ofthe steel strip to one another and mounted to move along the vesselbody; a portal which surrounds the body of the vessel and is movablealong the body of the vessel, said portal including an upper platform tosupport said technological line for preparation of the steel strip forits winding onto the central pipe of the vessel and a crossbar securedto uprights of the portal and movable vertically; said tensioning meanscarried by and movable along a crossbar that extends along the exteriorof the vessel and from which tensioning means the steel strip issupplied to the upper generatrix of the body of the vessel in such amanner that a free loop of the steel strip allows for pivoting of thetensioning means relative to the axis of the vessel body, said free loopformed between the technological line and the tensioning means.
 2. Amill according to claim 1, including an additional technological linefor preparation of the steel strip for its winding onto the central pipeof the body of the vessel and disposed on the upper platform of theportal; second means for tensioning the steel strip disposed on thecross-bar of the portal in the same horizontal plane as the first meansfor tensioning the steel strip, said technological lines beingpositioned, relative to the plane perpendicular to the axis of the bodyof the vessel, at an angle determined by the angle and direction ofwinding of the steel strip.